Criteria
for evaluating test item responses
- Using
the example of sitting around a campfire, give one example of how each
of the following heat transfer mechanisms might be occurring:
Radiation:
Sitting
around a campfire, you are heated by radiation from the fire.
Conduction:
A
stick you are using to heat marshmallows is heating along its length
by conduction.
Convection:
Heated
air is rising above the fire, or alternatively there may be a breeze
from a lake providing convection.
- How
are insulation and radiant barriers similar and different in terms of
heat transfer? Give an example of insulation.
Both
can be used to reduce heat transfer. In the example of the underside
of a hot roof deck, insulation may placed in contact with the roof deck
to reduce conduction from it into the attic. A radiant barrier may be
used under the roof deck as well— if the foil is facing up, it
will reflect heat back up to the roof deck and therefore reduce heat
transfer to the attic, or if the foil is facing down, the foil will
not emit the heat well to the attic space, therefore also reducing heat
transfer to the attic.
Examples of insulation might include bubble wrap, foam, newspaper, cardboard,
batt or blown fiberglass insulation.
- Both
infiltration and ventilation deal with outside airflow into and from
buildings. Explain the difference in how the airflow occurs in infiltration
and ventilation. Give an example of infiltration.
Examples
should identify a building that depicts air entering or exiting the
building unintentionally and also intended mechanical ventilation. The
mechanical ventilation may be used in the example as a means of providing
outside air to the building when the unintentional air leakage is sealed.
Examples of infiltration might include air leaks through cracks around
windows and under doors, leaky electrical outlets, etc.
Individual pages from this web site may be printed
and duplicated for
student classroom use
provided that proper credit is given to
the Florida Solar
Energy Center (FSEC).